假多晶型药物的表征

Solvated systems can be studied by techniques such as moisture sorption, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and isothermal calorimetry. Although in theory any one of these techniques can provide adequate data on the energy changes associated with solvation or desolvation, in practice isothermal microcalorimetry often provides superior data on pseudo-polymorphs, especially when only small (milligram) samples are available, or when unexpected results are obtained from other thermal techniques. For example, TGA was unable to detect formation of a drug hydrate in the presence of lactose monohydrate since there was no net change in mass associated with exchange of water between the drug substance and the lactose excipient.